Abstract
We have proposed the water curtain type underwater CO2 arc welding as a method of underwater welding. With this method we could make nozzle-to-work distance longer than 2-3 times compared with that for conventional underwater CO2 arc welding because of good shielding effects.
But, in case of welding with solid wires, welding speed was limited up to 30 cm/min. For the purpose of solution to this trouble, we tried single pass butt welding on mild steel at 0.3 m underwater by using flux cored wires.
Results obtained are as follows:
1) At high speed welding 120 cm/min as underwater welding, we succeeded to get good welds without blowholes and cracks.
2) The welds obtained from this method have excellent mechanical properties at bending test and tensile test.
3) Maximum hardness in welds was Hv 300.
4) This method had a weak point of poor visibility in the cause of melting of flux and slag into the water.
